The present invention relates to an engine control device for remote-controlling an engine of a boat, an industrial vehicle or the like. In this specification, the word "engine" has broad concept and includes also peripheral devices of engine, such as clutch.
There has been hitherto known an engine control device using a push-pull control cable. In such device, a remote control terminal or control box is operatively connected to an object engine through a push-pull control cable. Then operator's operation of a lever in the control box is transmitted to the engine side so as to control a governor in diesel engine or to change a forward/stop/reverse mode of clutch through the push-pull cable.
However, when the push-pull cable becomes long in arrangement length, control accuracy becomes low since frictional resistance and backlash become large. Further, manual operation becomes laborious due to large operational force.
Recently, several types of electric power-assisted engine control device are proposed, for example, in Japanese patent publications, Tokkai Hei3-249339, Tokkai Hei3-220093, Tokkai Hei3-253494. In those devices, a powered actuator is provided near an engine an output member of the actuator is connected with an input member of the engine through a short push-pull cable, and the device is constructed so that electric control signal is transmitted from the control box to the electric motor of the actuator. Among those publications, Tokkai Hei 3-220093 discloses an actuator which has an emergency lever capable of manually operating the push-pull cable. In the device, at a state of emergency, such as trouble of battery or power supply, the motor is disconnected and the device is enabled to be manually operated.
Further, the publication Tokkai Hei 3-253494 discloses a device which has not only a powered control system for remotely controlling a motor in the actuator, but also a manual remote control system for controlling the actuator by means of a push-pull cable, and further has a means for changing the systems by operating a solenoid actuator or the like. Further, the publication discloses a system changing mechanism in which an output of motor is transmitted to an inner cable of the push-pull cable for engine control and an output member for the manual operation is connected to a lever supporting an end of a conduit of the push-pull cable. The publication also discloses a device in which transmitting routes are changed by changing pivotal fulcrums of an output lever.
The device of Tokkai Hei3-220093 is inconvenience since operator should manually operate the actuator near the engine at the state of emergency. Further, the size of actuator is large since the device includes a rack and pinion mechanism.
On the other hand, though the device of Tokkai Hei3-253494 has an advantage that operator can manually operate at operator's seat in cabin, the changing mechanism is very complicated in structure, and the size is large. Further, in the device, input from electrically power-assisted operation route and input from manual operation route are composed by the changing mechanism so that the component is outputted, and the operation routes are mutually changed by blocking one route and operating another route. Therefore, when the device stops on the way of operation, the device must be changed from power mode to manual mode and be operated from such situation that is deviated from the normal operation area. Further, the operation to return the device into powered mode from manual mode is very complicated, since the device must be returned to a neutral position at once, the manual lever must be locked, and the like.
One of objects of the present invention is to provide an engine control device which can be remotely controlled from a skipper's seat in cabin, which is simple in construction, which can be easily changed in operation mode from powered mode to manual mode, and which can be operated in normal operation area after the change of mode.
Another object of the present invention is to provide an actuator suitable for the above engine control device.
Further another object of the present invention is to provide an engine control device which is easy in return operation from manual mode to power mode, and which can utilize a position detector for feedback control not only in power mode but also in manual mode.